1. Field of the Invention
The present invention relates to surgical tool handles for use in orthopedic implant surgery. More particularly, the present invention relates to a tool handle apparatus having a bias member mechanism for securing a surgical tool to a tool handle.
2. Prior Art
Surgical cutting tools are extensively used during orthopedic surgical procedures. Surgical tools such as broaches, rasps and other cutting devices are often used to prepare a patient's bone, such as during hip arthroplasty. For example, during a hip arthroplasty procedure, a surgeon may use a broach to prepare the inner surfaces of the intramedullary canal of a patient to receive a femoral hip prosthesis. This preparation of the intramedullary canal by the surgeon is designed to insure a proper fit between the patient's femur and the prosthesis.
However, regardless of the surgical procedure, it is important for a surgical tool to remain in a secure relationship to its handle. During a surgical procedure, mechanical forces and stresses are often applied to the connection points of these tools. Thus, connections between the tool and handle are sometimes prone to misalignment or even potential failure.
Various mechanisms have been used to attach a surgical tool to a handle. Examples of these mechanisms include a locking pawl mechanism disclosed in U.S. patent application Pub. No. 2012/0071862 to Burgi and the coil spring locking post assembly disclosed in U.S. Pat. No. 5,089,003 to Fallin et al.
In the '003 patent, a locking mechanism comprising a locking key 50 and a coil spring 52 is disclosed. As discussed by Fallin, a proximal end of a cutter 14 is positioned within an access opening 44 of the handle 12. Once positioned within the access opening 44, a locking key 50 which is compressed by a spring coil 56, is sprung into a “V” shaped notch 30 of the proximal end of the cutter 14. Thus, as the proximal end is positioned within the opening, the bias force of the coil spring 56 forces the locking key 50 within the notch, thereby locking the cutter 14 within the handle 12. The cutter 14 is released from the handle by drawing the locking post 50 in a proximal direction out from the notch, thereby freeing the cutter 14 from the handle 12. The locking post 50 is drawn in a proximal direction by use of a cable 70 that is connected to the locking post 50. Thus, as the cable 70 is drawn in a proximal direction, it moves the locking post 50 in a proximal direction, and out of the notch of the tool.
In U.S. patent application Pub. No. 2012/0071862, Burgi discloses a locking pawl 58 that pivotally positions an extending hook 68 in and out of a locking indentation 78A. Actuation of a lever arm causes the locking pawl 58 to pivotally position the hook end of the pawl in and out of the locking indentation 78A thus, securing a tool to the handle.
However, in contrast to the prior art, the tool handle of the present invention provides a bias member attachment mechanism that secures a surgical tool, such as a broach, rasp or cutting device to a handle. In the present invention, a tool connection member is positioned within the bias member, such as a coil spring, residing within the distal end of the handle. Actuation of the bias member, by an actuator, tightens the bias member around the connection member, thus securing the tool to the handle.
Thus, by constricting the bias member along a length of the connection member, a secure connection between the tool and the handle can be achieved. In contrast, the attachment mechanisms of the prior art have primarily relied on a point contact connection wherein the end of a hook or locking key provides the connection between the tool and the handle. The connection mechanism of the present invention provides a length of a bias member that wraps around a tool connection member, providing a greater contact area between the tool and handle and thus, a more robust connection is provided.
In addition, the reduced number of components comprising the bias member connection mechanism of the present invention provides a cost effective means of securing a surgical tool to a handle. Furthermore, the bias member connection of the present invention is also more conducive to manufacturing.